diff options
Diffstat (limited to 'daemon/cookie.c')
| -rw-r--r-- | daemon/cookie.c | 272 |
1 files changed, 0 insertions, 272 deletions
diff --git a/daemon/cookie.c b/daemon/cookie.c deleted file mode 100644 index 55f9621b..00000000 --- a/daemon/cookie.c +++ /dev/null @@ -1,272 +0,0 @@ -/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- - * - * GDM - The GNOME Display Manager - * Copyright (C) 2003 Red Hat, Inc. - * Copyright (C) 1998, 1999, 2000 Martin K. Petersen <mkp@mkp.net> - * Copyright (C) Rik Faith <faith@precisioninsight.com> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - */ - -/* - * Functions for generating MIT-MAGIC-COOKIEs. - * - * This code was derived (i.e. stolen) from mcookie.c written by Rik Faith - * - * Note that this code goes to much greater lengths to be as random as possible. - * Thus being more secure on systems without /dev/random and friends. - */ - -#include "config.h" - -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <fcntl.h> -#include <sys/time.h> -#include <unistd.h> -#include <errno.h> - -#include "gdm.h" -#include "md5.h" -#include "cookie.h" - -#include "gdm-common.h" -#include "gdm-daemon-config.h" - -#define MAXBUFFERSIZE 1024 - -static struct rngs { - const char *path; /* null is the authfile name */ - int length; - off_t seek; -} rngs[] = { - { "/dev/random", 16, 0 }, -#ifdef __OpenBSD__ - { "/dev/srandom", 16, 0 }, -#endif - { "/dev/urandom", 128, 0 }, - { "/proc/stat", MAXBUFFERSIZE, 0 }, - { "/proc/interrupts", MAXBUFFERSIZE, 0 }, - { "/proc/loadavg", MAXBUFFERSIZE, 0 }, - { "/proc/meminfo", MAXBUFFERSIZE, 0 }, -#if defined (__i386__) || defined (__386__) || defined (_M_IX86) - /* On i386, we should not read the first 16megs */ - { "/dev/mem", MAXBUFFERSIZE, 0x100000 }, -#else - { "/dev/mem", MAXBUFFERSIZE, 0 }, -#endif - /* this will load the old authfile for the display */ - { NULL /* null means the authfile */, MAXBUFFERSIZE, 0 }, - { "/proc/net/dev", MAXBUFFERSIZE, 0 }, - { "/dev/audio", MAXBUFFERSIZE, 0 }, - { "/etc/shadow", MAXBUFFERSIZE, 0 }, - { "/var/log/messages", MAXBUFFERSIZE, 0 }, -}; - -/* Some semi random spinners to spin, - * this is 20 bytes of semi random data */ -#define RANDNUMS 5 -static guint32 randnums[RANDNUMS]; - -/* stolen from XDM which in turn stole this - from the C standard */ -static guint32 -next_rand_15 (guint32 num) -{ - num = num * 1103515245 + 12345; - return (unsigned int)(num/65536) % 32768; -} - -/* really quite apparently only 31 bits of entropy result (from tests), - but oh well */ -static guint32 -next_rand_32 (guint32 num) -{ - int i; - guint32 ret; - guint8 *p = (guint8 *)&ret; - - for (i = 0; i < 4; i++) { - num = next_rand_15 (num); - p[i] = (num & 0xff00) >> 8; - } - return ret; -} - -/* This adds a little bit of entropy to our buffer, - just in case /dev/random doesn't work out for us - really since that normally adds enough bytes of nice - randomness already */ -void -gdm_random_tick (void) -{ - struct timeval tv; - struct timezone tz; - - gettimeofday (&tv, &tz); - - /* the higher order bits of the seconds - are quite uninteresting */ - randnums[0] ^= next_rand_32 ((tv.tv_sec << 20) ^ tv.tv_usec); - - /* different method of combining */ - randnums[1] ^= next_rand_32 (tv.tv_sec) ^ next_rand_32 (tv.tv_usec); - - /* probably unneeded, but just being anal */ - randnums[2] ^= (tv.tv_sec << 20) ^ tv.tv_usec; - - /* probably unneeded, to guess above - the number of invocation is likely needed - anyway */ - randnums[3]++; - - /* also hope that other places call - g_random_int. Note that on systems - without /dev/urandom, this will yet again - measure time the first time it's called and - we'll add entropy based on the speed of the - computer. Yay */ - randnums[4] ^= g_random_int (); -} - -/* check a few values and if we get the same - value, it's not really random. Likely - we got perhaps a string of zeros or some - such. */ -static gboolean -data_seems_random (const char buf[], int size) -{ - int i, lastval = 0; - if (size < 16) - return FALSE; - for (i = 0; i < 10; i++) { - int idx = g_random_int_range (0, size); - if G_LIKELY (i > 0 && - lastval != buf[idx]) - return TRUE; - lastval = buf[idx]; - } - return FALSE; -} - -static unsigned char old_cookie[16]; - -void -gdm_cookie_generate (char **cookiep, - char **bcookiep) -{ - int i; - struct GdmMD5Context ctx; - unsigned char digest[16]; - unsigned char buf[MAXBUFFERSIZE]; - int fd; - pid_t pid; - int r; - char cookie[40]; /* 2*16 == 32, so 40 is enough */ - - cookie[0] = '\0'; - - gdm_md5_init (&ctx); - - /* spin the spinners according to current time */ - gdm_random_tick (); - - gdm_md5_update (&ctx, (unsigned char *) randnums, sizeof (int) * RANDNUMS); - - /* use the last cookie */ - gdm_md5_update (&ctx, old_cookie, 16); - - /* use some uninitialized stack space */ - gdm_md5_update (&ctx, (unsigned char *) cookie, sizeof (cookie)); - - pid = getppid (); - gdm_md5_update (&ctx, (unsigned char *) &pid, sizeof (pid)); - pid = getpid (); - gdm_md5_update (&ctx, (unsigned char *) &pid, sizeof (pid)); - - for (i = 0; i < G_N_ELEMENTS (rngs); i++) { - const char *file = rngs[i].path; - - if G_UNLIKELY (file == NULL) - continue; - do { - int flags; - - flags = O_RDONLY | O_NONBLOCK; -#ifdef O_NOCTTY - flags |= O_NOCTTY; -#endif -#ifdef O_NOFOLLOW - flags |= O_NOFOLLOW; -#endif - - errno = 0; - fd = open (file, flags); - - } while G_UNLIKELY (errno == EINTR); - - if G_LIKELY (fd >= 0) { - /* Apparently this can sometimes block anyway even if it is O_NONBLOCK, - so use select to figure out if there is something available */ - fd_set rfds; - struct timeval tv; - - FD_ZERO (&rfds); - FD_SET (fd, &rfds); - - tv.tv_sec = 0; - tv.tv_usec = 10*1000 /* 10 ms */; - r = 0; - - if G_UNLIKELY (rngs[i].seek > 0) - lseek (fd, rngs[i].seek, SEEK_SET); - - if G_LIKELY (select (fd+1, &rfds, NULL, NULL, &tv) > 0) { - VE_IGNORE_EINTR (r = read (fd, buf, MIN (sizeof (buf), rngs[i].length))); - } - - if G_LIKELY (r > 0) - gdm_md5_update (&ctx, buf, r); - else - r = 0; - - VE_IGNORE_EINTR (close (fd)); - - if G_LIKELY (r >= rngs[i].length && - data_seems_random ((char *) buf, r)) - break; - } - } - - gdm_md5_final (digest, &ctx); - - for (i = 0; i < 16; i++) { - char sub[3]; - g_snprintf (sub, sizeof (sub), "%02x", (guint)digest[i]); - strcat (cookie, sub); - } - - if (cookiep != NULL) { - *cookiep = g_strdup (cookie); - } - - if (bcookiep != NULL) { - *bcookiep = g_new (char, 16); - memcpy (*bcookiep, digest, 16); - } - - memcpy (old_cookie, digest, 16); -} |